Sublethal effects on progeny production.

<p>Means (± SEM) of number of progeny produced in three d by each tested <i>Bracon nigricans</i> female exposed to 1-h (A) or to 10-d old pesticide residues (B) or by each emerged female from the treated cocooned pupae (C). For each figure, the bars followed by the same letter are not significantly different (<i>P</i>>0.05; ANOVA with Tukey HSD post hoc test for multiple comparisons).</p

Table 3. Statistics from the GLM Multivariate analysis used to test the effects of insecticide, residue age (1-h and 10-d), and of their interaction on the progeny production, progeny sex-ratio, and number of killed hosts.

<p>Table 3. Statistics from the GLM Multivariate analysis used to test the effects of insecticide, residue age (1-h and 10-d), and of their interaction on the progeny production, progeny sex-ratio, and number of killed hosts.</p

Statistics from the GLM Multivariate analysis used to test the effects of insecticide, sex, residue age (1-h and 10-d) and of the interaction of the insecticide factor with all the other ones on the adult mortality (survival) and on the longevity of the surviving adults.

<p>Statistics from the GLM Multivariate analysis used to test the effects of insecticide, sex, residue age (1-h and 10-d) and of the interaction of the insecticide factor with all the other ones on the adult mortality (survival) and on the longevity of the surviving adults.</p

Lethal effects.

<p>Mean percentages (± SEM) of survival of <i>Bracon nigricans</i> adults when exposed to 1-h (A) or to 10-d old pesticide residues (B). Mean percentages (± SEM) of <i>B. nigricans</i> emergences from treated cocooned pupae (C). For each figure, the bars followed by the same letter (lower case letters: female; upper case letters: male) are not significantly different (<i>P</i>>0.05; ANOVA with Tukey HSD post hoc test for multiple comparisons).</p

Sublethal effects on biocontrol activity.

<p>Means (± SEM) of number hosts killed in three d by one <i>Bracon nigricans</i> female exposed to 1-h (A) or to 10-d old pesticide residues (B) or by one emerged female from the treated pupae (C). For each figure, the bars followed by the same letter are not significantly different (<i>P</i>>0.05; ANOVA with Tukey HSD post hoc test for multiple comparisons).</p

Sublethal effects on longevity.

<p>Means (± SEM) of longevity (days) of <i>Bracon nigricans</i> adults exposed to 1-h (A) or to 10-d pesticide residues (B) or of those emerged from treated cocooned pupae (C). For each figure, the bars followed by the same letter (lower case letters: female; upper case letters: male) are not significantly different (<i>P</i>>0.05; ANOVA with Tukey HSD post hoc test for multiple comparisons).</p

Tested biopesticides.

<p>*Pesticides authorized also in organic farming.</p

Reduction coefficient <i>E_x</i>[48], IOBC toxicity classes [3], Doubling time (<i>DT</i>) and Intrinsic rate of increase (<i>r_m</i>) [25] estimated for adults exposed to 1-h old and 10-d old pesticide residues, for adults emerged from topically treated cocooned pupae, and for the control population [33].

<p>*Calculated only for acute toxicity.</p

Table_2_Volatiles of fungal cultivars act as cues for host-selection in the fungus-farming ambrosia beetle Xylosandrus germanus.xlsx

Many wood-boring insects use aggregation pheromones during mass colonization of host trees. Bark beetles (Curculionidae: Scolytinae) are a model system, but much less is known about the role of semiochemicals during host selection by ambrosia beetles. As an ecological clade within the bark beetles, ambrosia beetles are obligately dependent on fungal mutualists for their sole source of nutrition. Mass colonization of trees growing in horticultural settings by exotic ambrosia beetles can occur, but aggregation cues have remained enigmatic. To elucidate this mechanism, we first characterized the fungal associates of the exotic, mass-aggregating ambrosia beetle Xylosandrus germanus in Southern Germany. Still-air olfactometer bioassays documented the attraction of X. germanus to its primary nutritional mutualist Ambrosiella grosmanniae and to a lesser extent another common fungal isolate (Acremonium sp.). During two-choice bioassays, X. germanus was preferentially attracted to branch sections (i.e., bolts) that were either pre-colonized by conspecifics or pre-inoculated with A. grosmanniae. Subsequent analyses identified microbial volatile organic compounds (MVOCs) that could potentially function as aggregation pheromones for X. germanus. To our knowledge, this is the first evidence for fungal volatiles as attractive cues during host selection by X. germanus. Adaptive benefits of responding to fungal cues associated with an infestation of conspecifics could be a function of locating a suitable substrate for cultivating fungal symbionts and/or increasing the likelihood of mating opportunities with the flightless males. However, this requires solutions for evolutionary conflict arising due to potential mixing of vertically transmitted and horizontally acquired symbiont strains, which are discussed.</p

Data_Sheet_1_Volatiles of fungal cultivars act as cues for host-selection in the fungus-farming ambrosia beetle Xylosandrus germanus.docx

Many wood-boring insects use aggregation pheromones during mass colonization of host trees. Bark beetles (Curculionidae: Scolytinae) are a model system, but much less is known about the role of semiochemicals during host selection by ambrosia beetles. As an ecological clade within the bark beetles, ambrosia beetles are obligately dependent on fungal mutualists for their sole source of nutrition. Mass colonization of trees growing in horticultural settings by exotic ambrosia beetles can occur, but aggregation cues have remained enigmatic. To elucidate this mechanism, we first characterized the fungal associates of the exotic, mass-aggregating ambrosia beetle Xylosandrus germanus in Southern Germany. Still-air olfactometer bioassays documented the attraction of X. germanus to its primary nutritional mutualist Ambrosiella grosmanniae and to a lesser extent another common fungal isolate (Acremonium sp.). During two-choice bioassays, X. germanus was preferentially attracted to branch sections (i.e., bolts) that were either pre-colonized by conspecifics or pre-inoculated with A. grosmanniae. Subsequent analyses identified microbial volatile organic compounds (MVOCs) that could potentially function as aggregation pheromones for X. germanus. To our knowledge, this is the first evidence for fungal volatiles as attractive cues during host selection by X. germanus. Adaptive benefits of responding to fungal cues associated with an infestation of conspecifics could be a function of locating a suitable substrate for cultivating fungal symbionts and/or increasing the likelihood of mating opportunities with the flightless males. However, this requires solutions for evolutionary conflict arising due to potential mixing of vertically transmitted and horizontally acquired symbiont strains, which are discussed.</p